The present invention relates to disk brake mechanisms for motor vehicles.
A conventional disk brake mechanism is shown in FIGS. 8 and 9. Friction pads b1, b2 are provided on both sides of the rotor `a` as shown in FIG. 8, the rotor rotating with the vehicle wheel. The caliper c is arranged overriding the rotor `a` and carries the friction pads b1, b2. A bearing bore d as shown in FIG. 9 is formed at the opposite end of the caliper c from the friction pads. A camshaft e is installed in bearing bore d. The exposed portion e' of the camshaft e carries the brake lever f which is held in place by the nut g. A return spring h is arranged around the nut g and biases the lever f in one rotational direction. A push rod j is interposed between the camshaft e and the automatic adjustment mechanism i which in turn is connected to the brake piston (unshown).
The camshaft e is rotated when the lever f is pulled by the operating wire k. The push rod j makes the piston move forward through the automatic adjustment mechanism i to operate the friction pads b1, b2 to contact with the rotor `a`.
Certain difficulties exist with respect to the conventional structure. A small clearance l occurs between the brake lever f and camshaft e which leaves the lever slightly loose and requires further travel of the lever to achieve the desired level of braking. There exists the possibility that the nut g will loosen and fall off. If this occurs, the lever will also fall off. In operation, the mean diameter of the coil spring widens. In assembly, the nut g has to be put on and tightened. This increases the number of operations for assembly and also increases the number of parts.